Patient controlled bolus dosage infuser

ABSTRACT

An infusion system for the delivery of a first continuous flow of a intravenous fluid and second multiple selectable dosages of the fluid from a source to a site comprises a source of intravenous fluid under pressure, a housing having an inlet for connection to the source of fluid and an outlet for connection to a delivery site, a first passage in the housing for conveying a continuous constant low volume of the fluid to the outlet, and a second passage in the housing having an accumulator for accumulating a predetermined fixed charge of fluid and an actuator for selectively releasing the flow of the fluid from the accumulator to the outlet.

BACKGROUND OF THE INVENTION

The present invention relates to medical infusion devices, and moreparticularly, to an improved combination continuous dose and bolus doseinfusion system for delivering patient selectable controlled doses ofintravenous drugs at controlled intervals above a controlled rate.

It is often necessary to intravenously supply patients with doses ofpharmaceutically active liquids over a long period of time at acontrolled rate. It is desirable that this be accomplished while thepatient is in an ambulatory state.

The administration of effective doses of analgesics is highly subjectiveand depends on such factors as age, pain tolerance, renal function andother medications. For this reason, it is desirable that the patienthave a certain amount of control over the dosage. However, it is alsodesirable that overdose be prevented. Many devices have been availablein the past for allowing the self administration of analgesics. However,these have many drawbacks, including being bulky, complicated andexpensive. Most of such devices also provide only an on demand rush ofthe drug.

One prior art infusion apparatus having many desirable characteristicsis disclosed in U.S. Pat. No. 5,011,477, issued Apr. 30, 1991, toWinchell et al. This apparatus provides a combination of a continuousdose and a patient controlled bolus dose The device has the drawback ofbeing complicated and expensive to manufacture.

Accordingly, it would be desirable to provide an improved low costpatient controlled analgesic infusion system for delivering intravenousdrugs in a continuous background dosage, with the ability for patientselection of a bolus dose substantially on demand.

SUMMARY OF THE INVENTION

It is, therefore, the primary object of the present invention to providean improved low cost patient controlled analgesic infusion system fordelivering intravenous drugs in a continuous background dosage, with theability for patient selection of a bolus dose substantially on demand.

A primary aspect of the invention comprises a continuous source ofintravenous fluid, with an in line controller for providing a continuousbackground dose, and an accumulator with a patient activated valve forproviding a bolus dose substantially on demand.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and advantages of the present invention willbecome apparent from the following description when read in conjunctionwith the accompanying drawings wherein:

FIG. 1 is a front elevation view of a preferred embodiment of theinvention;

FIG. 2 is a sectional view of the fluid flow regulator of FIG. 1 showingdetails of construction and a first condition of the unit;

FIG. 3 is a section view taken on line 3--3 of FIG. 2;

FIG. 4 is a view like FIG. 3 showing the valve of the unit activated;and

FIG. 5 is a section view like FIG. 3 of an alternate embodiment.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring to FIG. 1 of the drawing, there is illustrated an infusionsystem in accordance with the invention comprising a source ofpressurized fluid, designated generally by the numeral 10, connected byway of the usual IV tubing 12 to a flow regulator device, designatedgenerally at 14, for controlling the flow of an intravenous fluid by wayof delivery tubing 16 to a patient. The system is designed as a patientcontrolled analgesic infusion device wherein the patient receives afirst or continuous low level dosage of an analgesic and mayperiodically select a bolus dosage as needed. The device is designed asa simple and inexpensive disposable unit that is simple, reliable andeasy to use. The source of pressurized fluid 10 is preferably aninflatable bladder infusor of such as disclosed in application Ser. No.07/492,982, filed Mar. 12, 1990, now U.S. Pat. No. 5,080,652, andentitled "Infusion Apparatus", said application incorporated herein byreference as though fully set forth.

The control unit 14 comprises a housing, which in the illustratedembodiment has a generally cylindrical configuration having an inlet endwall 18, with an inlet port or connection 20 connected to the source offluid 10 by tubing 12. An outlet end wall 22 includes an outlet port 24connected by IV tubing 16 to a patient. A transparent tubular shell orsleeve 26 is connected between the end wall members 18 and 22, and formsa generally cylindrical chamber within which is disposed a centrallygenerally step cylindrical body member 28, forming an elongated annularchamber extending coaxially of the housing.

The flow control unit 14 has means for providing a first fixedcontinuous flow of fluid therethrough at a first predetermined rate.This first means comprises a first passageway 30 communicating betweenthe inlet port 20 and an outlet port 24 by way of chamber 32 in which ismounted a metering orifice or capillary tube to provide a fixedcontinuous rate of flow. This is typically on the order of 0.5, 1.0 and1.5 ml/hr and may be called or termed a background flow.

Second means for providing a bolus dosage comprises a second inletpassage 34 communicating by means of a port 36, with an outer surface ofa reduced diameter portion of the support member 28. A chamber of cavity35 is provided to receive an orifice or capillary tube to regulate theflow to fill the bolus reservoir at predetermined periods, such as 6, 15or 60 minutes. An outlet passage 38 includes a port 40 communicatingfrom the surface of the cylindrical portion 28a of the central member.The ports 36 and 40 are axially spaced apart and are covered by means ofan elastic sleeve 42, which is preferably of silicone rubber and issealingly secured by suitable means, such as a plurality of O-rings 44,46 and 48 spaced axially along the tubular sleeve and cylindrical member28a.

The combination of the tubular elastic sleeve and the O-rings form abolus or accumulating reservoir 50 communicating initially solely withthe inlet port 36 of the inlet passage 34. This provides an accumulationreservoir which accumulates a predetermined charge or dosage of themedication.

An extended portion of the elastic sleeve 42 extends over and coversoutlet port 40 between O-rings 46 and 48. Thus, initially the chamber 50is sealed from the outlet and accumulates a charge of fluid by expandingwithin the annular chamber. In a preferred form, the accumulationreservoir 50 fills within a predetermined period of time, such asfifteen minutes or any other selected period of time.

Means are provided to release the accumulated fluid into the adjacentchamber wherein it may flow via outlet port 40 and passage 38 to theoutlet 24.

This release means comprises, as best seen in FIGS. 3 and 4, a generallyU-shaped pincher member 52, which partially encircles the entire outerhousing and includes inwardly directed fingers or grippers 54 and 56adjacent the ends thereof. These fingers extend through openings 58 and60 in the outer housing 26, and engage the surface of O-ring 46. Thesefingers have sharp edges which engage and grip the outer surface of theO-ring 46 when pressed inward as shown by the arrows at FIG. 4. Thispressure forces the O-ring 46 to bow outward releasing the force thereofon the surface of the bladder or sleeve 42. This allows the sleeve 42 tocup upward, as shown in FIG. 4, forming a passage 62 beneath and beyondthe O-ring 46 communicating with the outlet port 40. Thus, the O-ring 46and the extended portion of bladder functions as a valve to enable thefluid in chamber 50 to flow out the outlet 24 to provide the bolusdosage.

Referring to FIG. 5, an alternate embodiment of the valve activating orrelease means is illustrated and comprises a ring member 64 havinginwardly directed wedge shaped fingers 66 extending through holes 70 inthe outer housing 26' for engaging the O-ring 46. This arrangement has amore symmetrical construction and provides openings or passages onopposite sides of the central support member 28a.

In operation, a tubing set having an appropriate regulator is selectedand connected to a source of IV fluid and to the patient. The patient(or user) receives a continuous background flow of medication until theprescribed period within which he may obtain a bolus dose if desired. Ifa bolus dose is desired, the user squeezes the actuator member 52 torelease the accumulated dose from the bolus reservoir. Bolusadjustability may be achieved by moving O-ring 46 and the actuator 52along member 28a.

Glass capillary tubes for mounting into cavities or chambers 32 and 35are available from Beckton Dickenson Company on special order.

While we have illustrated and described our invention by means ofspecific embodiments, it should be understood that numerous changes andmodifications may be made therein without departing from the spirit andscope of the invention as defined in the appended claims. We furtherassert and sincerely believe that the above specification contains awritten description of the invention and the manner and process ofmaking and using it, in such full, clear, concise, and exact terms as toenable any person skilled in the art to which it pertains, or with whichit is most nearly concerned, to make and use the same, and further thatit sets forth the best mode contemplated by us for carrying out theinvention.

We claim:
 1. An infusion system for the delivery of a first continuousflow of an intravenous fluid and second multiple selectable dosages ofthe fluid from a source to a site, comprising:a source of intravenousfluid under pressure; tubing means including a flow regulator forconnecting said source of fluid to a delivery site; and said flowregulator comprising a housing having an inlet for connection to saidsource of fluid and an outlet for connection to a delivery site, firstpassage means in said housing communicating between said inlet and saidoutlet for conveying a continuous constant low volume of said fluid fromsaid inlet to said outlet, and second passage means in the housingcommunicating between said inlet and said outlet independent of saidfirst passage means having accumulator means for accumulating apredetermined fixed charge of fluid, and means for selectively releasingthe flow of the fluid from the accumulator means to the outlet.
 2. Aninfusion system according to claim 1 wherein said accumulator means isan elastic bladder.
 3. An infusion system according to claim 1 whereinsaid first passage means includes a capillary tube for establishing saidcontinuous constant low volume of said fluid to said outlet.
 4. Aninfusion system according to claim 3 wherein said second passage meansincludes flow restriction means for establishing a predetermined rate offlow to said accumulator means for accumulating a predetermined fixedcharge of fluid.
 5. An infusion system according to claim 1 wherein saidsecond passage means includes flow restriction means for establishing apredetermined rate of flow to said accumulator means for establishing apredetermined time period for accumulating a predetermined fixed chargeof fluid.
 6. An infusion system for the delivery of a first continuousflow of an intravenous fluid and second multiple selectable dosages ofthe fluid from a source to a site, comprising:a source of intravenousfluid under pressure; tubing means including a flow regulator forconnecting said source of fluid to a delivery site; said flow regulatorcomprising a housing having a generally tubular outer shell and anaxially extending inner cylindrical support member defining an annularchamber, an inlet for connection to said source of fluid and an outletfor connection to a delivery site, first passage means in said housingfor conveying a continuous constant low volume of said fluid to saidoutlet, and second passage means in the housing having accumulator meansfor accumulating a predetermined fixed charge of fluid and means forselectively releasing the flow of the fluid from the accumulator meansto the outlet; and said accumulating means comprising an elastic bladderdefined by a tubular sleeve mounted on said cylindrical support memberand confined without said tubular housing.
 7. An infusion systemaccording to claim 6 wherein:said elastic tubular sleeve is secured onsaid cylindrical support member by means of a pair of spaced apart endO-rings and an intermediate O-ring; and said means for selectivelyreleasing the flow comprises means for deforming the intermediate O-ringfor enabling fluid to pass beneath portions of said intermediate O-ring.8. A infusion system according to claim 7 wherein said means fordeforming the intermediate O-ring comprises means at least partiallyencircling said housing and having spaced apart finger means extendinginto said housing for engaging and deforming said intermediate O-ring inresponse to pressure thereon.
 9. An infusion system according to claim 7wherein said second passage mans is formed in said axially extendinginner cylindrical support member and includes a passage communicatingfrom said inlet to a surface thereof between a first of said end O-ringsand said intermediate O-ring, and an outlet passage communicating fromsaid surface thereof between a second of said O-rings and saidintermediate O-ring to said outlet port.
 10. An infusion system for thedelivery of a first continuous flow of an intravenous fluid and secondmultiple selectable dosages of the fluid from a source to a site,comprising:a source of intravenous fluid under pressure; tubing meansincluding a flow regulator for connecting said source of fluid to adelivery site; said flow regulator comprising a housing having an inletfor connection to said source of fluid and an outlet for connection to adelivery site, first passage means in said housing communicating betweensiad inlet and said outlet for conveying a continuous constant lowvolume of said fluid to said outlet, and second passage means in thehousing communicating between said inlet and said outlet independent ofsaid first passage means, having an elastic bladder for accumulating apredetermined fixed charge of fluid and means for selectively releasingthe flow of the fluid from the accumulator means to the outlet.
 11. Aninfusion system for the delivery of a first continuous flow of anintravenous fluid and second multiple selectable dosages of the fluidfrom a source to a site, comprising:a source of intravenous fluid underpressure; tubing means including a flow regulator for connecting saidsource of fluid to a delivery site; said flow regulator comprising ahousing having an inlet for connection to said source of fluid and anoutlet for connection to a delivery site, first passage means in saidhousing for conveying a continuous constant low volume of said fluid tosaid outlet, and second passage means in the housing having an elasticbladder for accumulating a predetermined fixed charge of fluid and meansfor selectively releasing the flow of the fluid from the accumulatormeans to the outlet, said housing having a generally tubular outletshell and an axially extending inner cylindrical support member definingan annular chamber; and said elastic bladder comprises a tubular sleevemounted on said cylinder support member and confined within said tubularhousing.
 12. An infusion system according to claim 11 wherein:saidelastic tubular sleeve is secured on said cylindrical support member bymeans of a pair of spaced apart end O-rings and an intermediate O-ring;and said axially extending inner cylindrical support member includes apassage communicating from said inlet to said sleeve between a first ofsaid end O-rings and said intermediate O-ring, and an outlet passagecommunicating from said sleeve between a second of said end O-rings andsaid intermediate O-ring to said outlet port.
 13. An infusion systemaccording to claim 12 wherein said means for selectively releasing theflow comprises means for deforming the intermediate O-ring for enablingfluid to pass beneath portions of said intermediate O-ring and saidsleeve.
 14. An infusion system according to claim 13 wherein said meansfor deforming the intermediate O-ring comprises means at least partiallyencircling said housing and having spaced apart finger means extendinginto said housing for engaging and deforming said intermediate O-ring inresponse to pressure thereon.
 15. An infusion system according to claim14 wherein said first passage means includes a capillary tube forestablishing said continuous constant low volume of said fluid to saidoutlet; andsaid second passage means includes flow restriction means forestablishing a predetermined rate of flow to said accumulator means foraccumulating a predetermined fixed charge of fluid.
 16. An infusionsystem for the delivery of a first continuous flow of a fluid and secondmultiple selectable dosages of an intravenous fluid from a source to asite, a flow regulator comprising:a housing having an inlet forconnection to a source of fluid and an outlet for connection to adelivery site; first passage means in said housing for conveying acontinuous constant low volume of said fluid from said inlet to saidoutlet; and second passage means in the housing independent of siadfirst passage means having accumulator means for accumulating apredetermined fixed charge of fluid and means for selectively releasingthe flow of the fluid from the accumulator means to the outlet.
 17. Aninfusion system for the delivery of a first continuous flow of a fluidand second multiple selectable dosages of an intravenous fluid from asource to a site, a flow regulator comprising:a housing having an inletfor connection to a source of fluid and an outlet for connection to adelivery site; first passage means in said housing for conveying acontinuous constant low volume of said fluid to said outlet; and secondpassage means in the housing having accumulator means for accumulating apredetermined fixed charge of fluid and means for selectively releasingthe flow of the fluid from the accumulator means to the outlet, saidhousing has a generally tubular outer shell and an axially extendinginner cylindrical support member defining an annular chamber, saidaccumulator means comprising an elastic tubular sleeve secured on saidcylindrical support member by means of a pair of spaced apart endO-rings and an intermediate O-ring, and said axially extending innercylindrical support member includes a passage communicating from saidinlet to said sleeve between said first O-ring and said intermediateO-ring, and an outlet passage communicating from said sleeve betweensaid second O-ring and said intermediate O-ring to said outlet port. 18.An infusion system according to claim 17 wherein said means forselectively releasing the flow comprises means at least partiallyencircling said housing and having spaced apart finger means extendinginto said housing for engaging and deforming the intermediate O-ring forenabling fluid to pass beneath portions of said intermediate O-ring andsaid sleeve.
 19. An infusion system according to claim 18 wherein saidfirst passage means includes a capillary tube for establishing saidcontinuous constant low volume of said fluid to said outlet; andsaidsecond passage means includes flow restriction means for establishing apredetermined rate of flow to said accumulator means for accumulating apredetermined fixed charge of fluid.